The present invention relates in general to thermal breaks which provide an insulated and supporting connection between two or more juxtaposed frame members, and, more particularly, to a thermal barrier apparatus and process for fabricating same wherein the thermal break comprises a stretchable attachment strip which is stretchable to a reduced shape for insertion into a strip acceptance channel of corresponding frame members, and then recoverable to a recovered restraining shape which binds the frame members together in a restrained insulated position.
Traditionally, thermal barriers, and more particularly thermal barriers having juxtaposed metal frame members, have been fabricated by extruding metal, such as aluminum, through a single die, to in turn create two frame members which are physically attached by a U-shaped cavity. After the frame members have been extruded, an insulating material, such as polyurethane, is eventually inserted within the cavity. An example of such prior art is U.S. Pat. No. 4,704,839. Insertion of the insulating material typically results by pouring a prepared thermal set urethane liquid into the U-shaped cavity of the extrusion. Of course, prior to such pouring, the ends of the cavity must be temporarily plugged so as to maintain the urethane liquid therewithin.
After the urethane liquid has been poured into the cavity, it must set until it hardens. Unfortunately, the appropriate hardness may take as much as up to twenty-four hours to achieve. Regardless, after the urethane has properly hardened, the temporary plugs should be removed from the cavity ends, and then the portion of the extrusion forming the bottom of the cavity must be cut away so as to form two or more separate metal frame elements having a contiguous profile with a thermal break.
Although such thermal barriers have been effective, they have, and do, result in unnecessary expense and delays in fabrication. For example, inasmuch as the extrusion of the frame members result in two united frame members physically attached to each other, the unit must be painted together. Accordingly, should it be desirous to have one half of the frame painted one color, and the other half painted another (such as for a window frame for a building where the outside portion of the frame is to be painted the color of the outside of the building, and the inside portion of the frame is to be painted the color of an inside room) the frame members must be masked off for each such color to be painted.
Other problems which can result from poured insulating material is that an incorrect amount of catalyst can be mixed in with the insulating material--thus resulting in a defective thermal break. The defective thermal break must then be cut out, removing portions of the aluminum extrusions in the process, thereby destroying the possibility of reusing those extrusions for anything other than recyclable scrap. Recycling of the aluminum extrusions in a melting operation can not be done with the thermal break in place because it would contaminate the metal and also would damage the environment. Furthermore, inasmuch as the frame members in such prior art are extruded with the connecting cavity, extra material must be used and extra processes must be utilized for removal of the cavity material after the insulating material has effectively cured.
Although thermal barriers which utilize two separately extruded frame portions and a non-poured insulating insert for providing a thermal break therebetween have been known in the art for many years, such art does not teach, much less disclose a stretchable insulating strip which is stretchable to a reduced insertion shape and then recoverable to a recovered restraining shape. An example of a thermal barrier utilizing two separate frame members and a non-poured insulating strip is U.S. Pat. No. 3,411,254. Although the '254 patent discloses a thermal barrier which utilizes a pre-formed thermal break constructed from a plastic material which is slideably inserted into the channels of two corresponding frame members, the plastic strip itself is formulated with an internally mixed blowing agent. This blowing agent causes slight expansion of the strip upon exposure of heat. The blowing agent results in an uncontrolled expansion of the plastic strip during such exposure to heat which could result in scrap generation with attendant problems similar to those associated with poured thermal break systems. In addition, the channels of the frame members preferably include flanges which are bent, or crimped, into the plastic strip after insertion and prior to exposure to the heat so as to "lock" the plastic strip in place.
It is thus an object of the present invention to provide a thermal barrier apparatus which utilizes an extruded attachment strip which is stretchable to a reduced insertion shape and then recoverable to a recovered restraining shape which binds two or more juxtaposed frame members together in a restrained insulated orientation.
It is further an object of the present invention to provide a thermal barrier apparatus which maintains such restrained binding as the result of expansion forces being applied within the strip acceptance channels of the frame members.
It is also an object of the present invention to provide a thermal barrier apparatus which is constructed from independent frame members so as to preclude the need for extra material usage, the extra process needed for removal of such material, as well as the extra process required to mask the different halves of an otherwise unitary frame member when different colors of paint are required for each of the frame member portions.
It is still further an object of the present invention to provide a thermal barrier apparatus which utilizes an extruded stretchable thermal strip to mechanically join the two or more juxtaposed frame members together so as to provide a contiguous thermally broken profile, and, to ensure consistent quality control for each of the strips so extruded.
And, it is also an object of the present invention to provide a thermal barrier apparatus which can be manufactured quickly and relatively inexpensively, and, without the need to use more material than is necessary for the finished product.
These and other objects of the present invention will become apparent in light of the present specification and drawings.